My client is having the following, and I need clarification on how to define these:

3 Operating Units (which are also Legal Entities)

3 Project/Task Owning Organization (which are also defined as Expenditure/Event Organization and Project Invoice Collection Organization). These are representing Balancing Segments and used to generate Profit and Loss Accounts and Balance Sheet reports.

I need to assign all the 3 P/T Ownings Orgs to each Operating Unit. My question is, while defining Organization Hierarchies, should I create 3 OUs and 9 (3*3) Project/Task Owning Organizations?

Or is there any alternative possible? I am thinking about define three different hierarchies for three OUs. Is this right option? Or is there any other options available for us? Please give me your valuable suggestions.